1
2#include <errno.h>
3#include <netdb.h>
4#include <stdio.h>
5#include <stdlib.h>
6#include <string.h>
7#include <unistd.h>
8#include <linux/types.h>
9#include <sys/socket.h>
10
11int main(int argc, const char **argv)
12{
13 char cbuf[CMSG_SPACE(sizeof(__u32))];
14 struct addrinfo hints, *ai;
15 struct cmsghdr *cmsg;
16 struct iovec iov[1];
17 struct msghdr msg;
18 int mark;
19 int err;
20 int fd;
21
22 if (argc != 4) {
23 fprintf(stderr, "Usage: %s <dst_ip> <port> <mark>\n", argv[0]);
24 return 1;
25 }
26 mark = atoi(argv[3]);
27
28 memset(&hints, 0, sizeof(hints));
29 hints.ai_family = AF_UNSPEC;
30 hints.ai_socktype = SOCK_DGRAM;
31
32 ai = NULL;
33 err = getaddrinfo(argv[1], argv[2], &hints, &ai);
34 if (err) {
35 fprintf(stderr, "Can't resolve address: %s\n", strerror(errno));
36 return 1;
37 }
38
39 fd = socket(ai->ai_family, SOCK_DGRAM, IPPROTO_UDP);
40 if (fd < 0) {
41 fprintf(stderr, "Can't open socket: %s\n", strerror(errno));
42 freeaddrinfo(ai);
43 return 1;
44 }
45
46 iov[0].iov_base = "bla";
47 iov[0].iov_len = 4;
48
49 msg.msg_name = ai->ai_addr;
50 msg.msg_namelen = ai->ai_addrlen;
51 msg.msg_iov = iov;
52 msg.msg_iovlen = 1;
53 msg.msg_control = cbuf;
54 msg.msg_controllen = sizeof(cbuf);
55
56 cmsg = CMSG_FIRSTHDR(&msg);
57 cmsg->cmsg_level = SOL_SOCKET;
58 cmsg->cmsg_type = SO_MARK;
59 cmsg->cmsg_len = CMSG_LEN(sizeof(__u32));
60 *(__u32 *)CMSG_DATA(cmsg) = mark;
61
62 err = sendmsg(fd, &msg, 0);
63
64 close(fd);
65 freeaddrinfo(ai);
66 return err != 4;
67}
68
